144 Contributions to Electricity and Magnetism. 
times less; and these inferences I have found in accordance with 
the results of experiments, (75.) If, however, instead of placing 
the helix on one spire of the long conductor, it be submitted at 
once to the influence of all the twenty spires, then the intensity 
of the shock should be twenty times greater, since twenty times 
the quantity of current electricity collapses, if we may be allow- 
ed the expression, in the same time, and exerts at once all its in- 
fluence on the helix. If, in addition to this, we add the conside- 
ration that the whole quantity of current electricity in a long 
conductor is greater than that in a short one, (73,) we shall have 
a further reason for the increase of the terminal shock, when we 
increase the length of the battery conductor. 
_ 75. The inference given in the last paragraph, relative to the 
change in the quantity of the induction, but not in the intensity 
of the shock from a single spire, by increasing the whole length 
of the conductor, is shown to be true by repeating the experiment 
described in paragraph 13. In this, as we have seen, the inten- 
sity of the shock remained the same, although the length of the 
circuit was increased by the addition of coil No. 2. When, how- 
ever, the galvanometer was employed in the same arrangement, 
the whole quantity of induction, as indicated by the deflection 
of the needle, was diminished almost in proportion to the increas- 
ed length of the circuit. I was led to make this addition to the 
experiment (13) by my present views. 
76. The explanation given in paragraph 74, also includes that 
of the peculiar action of a long conductor, either coiled or ex- 
tended, in giving shocks and sparks from a battery of a single 
element, discovered by myself in 1831; (see Contrib. No. IL) 
The induction, in this case, takes place in the conductor of the 
_ primary current itself, and the secondary current which is produ- 
ced is generated by the joint action of each unit of the length of 
the primary current. Let us suppose, for illustration, that the 
conductor was at first one foot long, and afterwards increased to 
twenty feet. In the first case, because the short conductor would 
transmit a greater quantity of electricity, the secondary current 
produced by it would be one of considerable quantity, or power 
to deflect a galvanometer; but it would be of feeble intensity, 
for although the primary current would collapse with its usual 
velocity, (69,) yet, acting on only a foot of conducting matter, 
the effect (74) would be feeble. In the second case, each foot 
et ie he 
